Joseph Engh was visiting his father in San Francisco six months ago when he noticed something was wrong.

His 89-year-old father, Moy Ng, seemed surlier than usual, and a little forgetful. Ng had developed pneumonia, which had prompted Engh's visit, so Engh took his father to see his doctor.

Ng, it turned out, has Alzheimer's disease - he might have had it for months or even years. But Ng lived alone, and with no family or close friends around to notice his memory loss or personality changes, getting him diagnosed and treated was a challenge.

"The doctor had known for some time that my father was having a problem. But he kind of refused to get diagnosed," said Engh, 63, who lives in Seattle.

Roughly 800,000 people in the United States have Alzheimer's and live alone, according to an Alzheimer's Association report released today. That's about 1 in 7 people who have Alzheimer's - and the rate is probably higher in big cities, where elderly adults are more likely to live alone. In San Francisco, public health experts estimate that up to 40 percent of people with Alzheimer's or other forms of dementia live alone.

Alone and at risk

Without someone to watch over them, these patients are at increased risk for malnutrition, accidents at home, and complications from misusing or overdosing medications. They tend to be diagnosed later than those who live with a spouse or other family member and they tend to end up in nursing homes earlier.

"They usually don't get referred to us until the problem gets to a critical stage, where they might start missing doctor appointments or not taking medicines or not paying rent and getting evicted," Boxer said. "By that point, someone is fairly advanced in their disease."

As Baby Boomers get older, and as more Americans live alone - often separated from families that have long departed for other cities - doctors and public health experts expect the number of people facing dementia on their own to increase.

With that in mind, they're working now to develop support systems to try to identify and diagnose people as soon as possible. The idea is to get patients the support they need before the disease has progressed to the point where they can no longer care for themselves.

Early treatment

There is no cure for Alzheimer's, but drugs can slow the disease, if patients start treatment early enough.

Patients who are diagnosed early also can start preparing for the disease's inevitable progression - by filling out forms expressing their health care wishes, appointing someone to take over their finances, and even arranging for services like transportation and meal delivery that they may need later on.

Plenty of services

A lot of services exist for older adults who have dementia, but if patients don't have someone to help them apply for those services, they may not get the help they need, said Cynthia Barton, a geriatric nurse practitioner at UCSF's Memory and Aging Center.

"Filling out forms, navigating the system, these kinds of things can be overwhelming," Barton said. "It can be cumbersome for all of us. It can be quite a challenge for someone with cognitive problems."

These gatekeepers might include mail carriers, police officers, church members and even salon workers and grocery clerks who have regular contact with customers. In theory, they are people who would know to look out for basic symptoms - an elderly woman who starts missing Sunday church services, for example, or a man who has stopped picking up his mail.

"If you have an environment where people are looking out for each other, that helps to protect people who are more vulnerable," Scharlach said. "But most of us don't have that."

Seeking help

Boxer suggests that anyone who is concerned about an older adult's cognitive health "encourage that person to come in for an evaluation." If the person refuses and there's concern that his or her health is at risk, adult protective services should be contacted, he said.

"I would talk to the person first, but don't leave it at that," Boxer said. "If, in your heart of hearts, you're worried they're not fine, you should take it a step further. I'd rather be wrong and embarrass the person a little bit than to miss this. ... You have to be tough in these situations."

That's what Engh is learning now. His father, he said, was always difficult, but he gets angry, and sometimes even violent, when he's reminded of his Alzheimer's diagnosis.

Engh realized that he couldn't leave his father entirely on his own, so at least for now, he lives part time in San Francisco to be near him - to take him to doctors' appointments, make sure he's eating enough and pay his bills.

"Medically, he's fine," Engh said. "He can bathe himself and clean and cook. He loves being on his own at home."

But Engh knows it's a matter of time. "I don't know how long that will last."

Getting help

To get help for someone who may have Alzheimer's disease or another form of dementia, contact the Alzheimer's Association 24-hour help line, (800) 272-3900, or San Francisco's Adult Protective Services, (415) 355-6700.